Despite advances in the medicinal arts, there remains a demand for treating pathologies of the hematopoietic system, such as diseases of a particular blood cell, metabolic disorders, cancers, and autoimmune conditions, among others. While hematopoietic stem cells have significant therapeutic potential, a limitation that has hindered their use in the clinic has been the difficulty associated with releasing hematopoietic stem cells from the bone marrow into the peripheral blood of a donor, from which the hematopoietic stem cells may be isolated for infusion into a patient. There is currently a need for compositions and methods for promoting the mobilization of hematopoietic stem and progenitor cells, and particularly for methods of identifying populations of mobilized cells that are suitable for therapeutic use.